Abstract: A counterbalance mechanism counterbalances an eccentric mass on a rotating shaft supported by a frame. A first pulley is coupled to and concentric with the shaft. An arm is coupled to the shaft to rotatably support a second at a first distance from the first pulley. A third pulley is fixedly coupled to the frame at a second distance from the first pulley. A fourth pulley is rotatably coupled to and concentric with the third pulley. A spring is fixed at a first end to the frame and has a second end that is coupled to the fourth pulley such that the spring provides a restoring force as the fourth pulley is rotated. A first cable has a first end that is coupled to the fourth pulley and a second end that is coupled to the frame through the third pulley after passing over the first and second pulleys.

Abstract: A buffer station provides potential improvement for the operation of a facility. By storing to-be-accessed workpieces in the buffer stations of an equipment, the operation of the facility is not interrupted when the equipment is down. The workpieces can be retrieved through emergency access port of the buffer station, thus ensure the continuous supply of workpieces for the workpiece flow of the facility. Algorithm for getting the needed workpieces to the buffer station is also provided through a controller or a computer mechanism. The buffer station can be incorporated in a stocker, such as wafer stocker or reticle stocker.